A scientific report published in September 2012 noted that emerging studies had associated prenatal bisphenol A (BPA) exposure with elevated hyperactivity and anxiety in young girls. This suggested a possibility that developmental exposure to endocrine disruptors like BPA might contribute to the growing prevalence of behavioural and mood-related disorders in children. To explore this further the scientists used rodents as an experimental model in trying to establish how chronic, low dose oral exposure to BPA throughout development might impact affective behaviour during adolescence and adulthood. They further studied the underlying molecular changes to the nervous system related to such effects and looked at the potential for dietary intervention with a soy-rich diet to mitigate BPA effects.
Assessment of serum BPA confirmed that the internal dose was within the human range of 2 ng/ml of unconjugated BPA reported in several studies. At this level BPA was shown to induce anxiogenic behaviour in juveniles and loss of sexual dimorphisms in adult exploratory behaviour, but only in the animals reared on the soy-free diet. Changes were identified in the amygdala region of the brain. Expression analysis revealed a number of genes associated with BPA-induced juvenile anxiety in rats, including a subset known to mediate sociosexual behaviour. Overall, the results showed that behavioural impacts of BPA can manifest during adolescence, but wane in adulthood, and may be mitigated by diet. The data also revealed that receptors linked to oxytocin/vasopressin signalling pathways, previously associated with human affective disorders, might have been involved in the behavioural changes.
Patisaul et al. (2012). Anxiogenic Effects of Developmental Bisphenol A Exposure Are Associated with Gene Expression Changes in the Juvenile Rat Amygdala and Mitigated by Soy. PLoS ONE 7(9): e43890. doi:10.1371/journal.pone.0043890